[PATCH v13 09/11] KVM: VMX: Add VMCS dump and sanity check for CET states

Yang Weijiang
2020-07-01T08:04:36Z

Dump CET VMCS states for debug purpose. Since CET kernel protection is
not enabled, if related MSRs in host are filled by mistake, warn once on
detecting it.

Signed-off-by: Yang Weijiang <weijiang.yang@intel.com>
---
arch/x86/kvm/vmx/vmx.c | 23 +++++++++++++++++++++++
1 file changed, 23 insertions(+)

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 32893573b630..70cb2d4a1391 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -5941,6 +5941,12 @@ void dump_vmcs(void)
pr_err("InterruptStatus = %04x\n",
vmcs_read16(GUEST_INTR_STATUS));

+ if (vmentry_ctl & VM_ENTRY_LOAD_CET_STATE) {
+ pr_err("S_CET = 0x%016lx\n", vmcs_readl(GUEST_S_CET));
+ pr_err("SSP = 0x%016lx\n", vmcs_readl(GUEST_SSP));
+ pr_err("SSP TABLE = 0x%016lx\n",
+ vmcs_readl(GUEST_INTR_SSP_TABLE));
+ }
pr_err("*** Host State ***\n");
pr_err("RIP = 0x%016lx RSP = 0x%016lx\n",
vmcs_readl(HOST_RIP), vmcs_readl(HOST_RSP));
@@ -6023,6 +6029,12 @@ void dump_vmcs(void)
if (secondary_exec_control & SECONDARY_EXEC_ENABLE_VPID)
pr_err("Virtual processor ID = 0x%04x\n",
vmcs_read16(VIRTUAL_PROCESSOR_ID));
+ if (vmexit_ctl & VM_EXIT_LOAD_CET_STATE) {
+ pr_err("S_CET = 0x%016lx\n", vmcs_readl(HOST_S_CET));
+ pr_err("SSP = 0x%016lx\n", vmcs_readl(HOST_SSP));
+ pr_err("SSP TABLE = 0x%016lx\n",
+ vmcs_readl(HOST_INTR_SSP_TABLE));
+ }
}

/*
@@ -8075,6 +8087,7 @@ static __init int hardware_setup(void)
unsigned long host_bndcfgs;
struct desc_ptr dt;
int r, i, ept_lpage_level;
+ u64 cet_msr;

store_idt(&dt);
host_idt_base = dt.address;
@@ -8236,6 +8249,16 @@ static __init int hardware_setup(void)
return r;
}

+ if (boot_cpu_has(X86_FEATURE_IBT) || boot_cpu_has(X86_FEATURE_SHSTK)) {
+ rdmsrl(MSR_IA32_S_CET, cet_msr);
+ WARN_ONCE(cet_msr, "KVM: CET S_CET in host will be lost!\n");
+ }
+
+ if (boot_cpu_has(X86_FEATURE_SHSTK)) {
+ rdmsrl(MSR_IA32_PL0_SSP, cet_msr);
+ WARN_ONCE(cet_msr, "KVM: CET PL0_SSP in host will be lost!\n");
+ }
+
vmx_set_cpu_caps();

r = alloc_kvm_area();
--
2.17.2